Insecticide



Patented June 3, 1947 .msnorrcms Frederick B. La

Forge, Arlington, Va., assignor to United States of America, as represented by the Secretary of Agriculture No Drawing. Application mm 4, 1944, a Serial No. 551,215

t scat- (01.167-24) (Granted under the act of March 3, 1883, as

V .1 'I'his application is madeunder the act of March- 3', 1883,as amended by the act of April 30, 1928,'and'the inventionherein described, it

patented, may b manufactured and used by or for the Government of the United States of America for governmental purposes without the payment tome ofany royalty thereon. Q j This invention relates to insecticidal compositions containingflpyrethrum and has "for its ob. ject the provision or an improved composition amended April 30, 1928; 3700. G. 757) ties in itself, increases the toxicity of the pyrethrins to a decidedly advantageous extent. Thus: 'I have found that,alpha-(3,4-methylenedioxyphenyl) tetrahydropyran, when incorporated with the pyrethrin's in an, appropriate solvent, yields an. insecticidal composition which is more eflective against the ordinary housefly than can be accounted for on the basis oifthepyrethrinand of this type. This invention further relates to the synthesis of anew compound, namely, alpha- (3 4 methylenedioxyphenyl)tetrahydropyran,

which is particularly useful "when employed in conjunction with pyrethrins becauseot the resulting synergistic actlon,"and also when employedasasolvent. I,

Insecticidal compositions containing pyrethrum are widely'used to combatinsectpests,.suoh' aa flies, mosquitoes, gnats, and the'like. Frequent-A ly, the pyrethrum is employed in a solvent or the alpha 3 4-methylenedioxyphenyl)tetrahydropyran content. Also, I have found that alpha- (3,4-methylenedioxyphenyl) tetrahydropyran is a good solvent for dichlorodiphenyltrichloroethanes, and in. particular, DDT, which is known to be toxic to household insects, but which is insoluble in certain liquefied gases, such as dichlorodifluoromethane. This solvent action is so great that alpha i 3 4-methy1enedioxyphenyl)tetrahydropyran may be used to keepdichlorodiphenyltrihydrocarbon or mineral oil type; such as odorless kerosene, naphthaand so forth. Also, it

is employed in a. solvent ofiliquelled gases, such as dichlorodifluoromethane, methyl chloride, and

so forth.- While these insecticidal compositions have good toxic properties and are well for the control or household insects and-the like,

they are expensive. t Y

I have found that a new compound, namely,

However, I donot restrict my inventiontothis composition and the new insecticidal ingredients may be used inlot her solvents and in comalpha-(3 4 methylenedioxyphenyl)tetr ahydropyran, represented by FormulaI,

Formula I' while possessing little or no lmectlcidal proper- Formula [II 'chloroethane in solution in the liquefied gas either with or without the Dyrethrins depending on the purpose of the insecticide. f

I preferas the insecticidal composition a combination of alpha-(3,4-methylenedioxyphenyl) j 'tetrahyclropyran and the pyrethrlns in either odorless kerosene or dichlorodifluoromethane.

bination' with other insecticides, such as organic thiocyanates, the like.

'Alpha- (3A-methylehedioxyphenyl) tetrahydro- I 'pyran, anew compoundQmay be prepared by the following procedure: r

The sodium compound of beta-hydroxy-beta- (3,4-methyienedloxy-phenyl)acrylic ethyl ester (Formula II) is caused to react with trimethylenebromide, as illustrated below, to furnish the ethyl ester of 2,3-dihydro-6- (3,4-methylenedioxyphenyl)-1,4-pyran-5-carboxylic acid (Formula.

IIDI.

+ 'Brcmomomar rot enone, derris, lonchocarpus, and V The ester is saponified with ethanolic potassium hydroxide to the potassiurn'salt of the corresponding acid which is obtained on" addition of hydrochloric acid. The free acid, on heating, loses carbon dioxide to furnish 2,3.-dihydro-6- (3,4-methylenedioxyphenyl)-1,4-pyran (Formula,

IV),whichis' m H2O HVH, Y H2 FormulalV This is then reduced with hydrogen in the -pi-es-- ence of a platinum catalyst ina'convent'ional' manner to alpha (3,4-methylenedioxyphenyl)- tetrahydropyran as shown inFormula I.

Combustion analysis for carbon andhydrogen gave values of 69.36 percent for carbon and. 6.85 percent for hydrogen whichlcompares favorably with the theory of 69.89 DQl'cent and 6.85 percent;

respectively. Therefractive index at 26 C. for the yellow sodium line was found'to be 1.5436a'nd the specific gravity at 26 C. was found to be The efficiency of alpha- (3,4- methylenedioxy-... F

phenyl) tetrahydropyran is shown. by. th followingresults:

1. A refined kerosene'solution of l-percent of the above compound'alone gave a 4 percent :kill

of housefiies in 48 hours.

2. A refined kerosene solution containin htfld percent of pyrethrins alone gave a killof 17 percent in 48 hours. i y p 3. A refined kerosene .solution containing 1 pyrethrins rnay be varied over a wide range trom to 1'? part by weight of pyrethrins, from I to 20parts by weight of al'pha (3;4-methylencdioxyphenyl)tetrahydropyran, and from, 98.95 to '79 parts by weight of kerosene. "-Having thus described my invention. I claim:

1.7 An insecticidal composition COITlDi'lSiilgpyrethrum and alpha-i3;4-methylenedioxyphenyl-i-- Ttetrahydropyran as a synergist therefor.

2. An insecticidal composition comprising py- .rethrurn' and alphan-(3,4-methylenedioxyphenyiJ'- tet'rahydropyran as a synergist therefore. is dissolved in-a mutual solvent.

An insecticidal composition comprisin p;v rethrum and alpha (3,4-methylenedoxyphen vi) I ftetra-hydropyran as a synergist therefor; dissolved in a mineral oil base.

4;. An insecticidal composition comprising l b1- g rethruin and alpha-i3;4-methylenedioxyphe1131i.

ttrahydropyian as'asynergist therefor; dissolved in dichlorodifiuoi'omethane.

jfi An'insecticidal. composition comprising from,

,i 0.05 to l part by weight of pyrethrins and from as. p I

"luti'on' of jpyrethrum, alpha-(3,4-methylenedioxypercent of the abovenew compound and, in ad dition, .05 percent of pyrethrins gave a kill or 99 percent ofthe houseflies in 48 hours; Itls thus obvious that a very small concentration. of the compound which in itself is ineflfectivegives a pronounced increase in killing power of .the diluted pyrethrin solution. This killing'power is greater than that of the average commercial fly spray which contains twice the amount of pyrethr'ins used in the above test. The resultisa considerable saving of pyrethrins. 0

The above example is by illustration only and the amount and proportion of alpha-(3,4-rnethylenedioxyphenyl)tetrahydropyran and oithe fiuoromethane.

1 to '20 parts by weight of alpha'-5(3:,-methylenedioxyphenyl) tetrahydropyran, dissolved; in: 9.8.95

to '79 parts'byweight of kerosene.

6. An insecticidal composition comprising dichlorodiphenyltrichloroethane. dissolved in. al-- pha (3 4 4 methylenedioxyphenyl) tetrahydropyran." H v 7. An'insecticidalcomposition comprising asu- Lution of, dichlor odiphen'yltrichloroethane,v al pha (3,4-methylenedioxyphenyll tetrahydropyran, and

dichlorodifiuoromethanel a 8.,An insecticidalcompositionv comprising a sophenylltetrahydropyran ass, synergist therefor, dichlorodiphenyltrichloroethane and dichlorocli- I rirucnnruckrn. LA FORGE.

{REFERENCES CITED following references are ofirecord in the file-oi this patent:.

'UNITED STATES PATENTS Number .Name Date 2,251,128? Lott lAUg. 194] 6.350 Gertler et 3.1. Aug. ill), 1943 

